Google search tracks spread of flu across US

Nov 12, 2008, 14:56 GMT

San Francisco - Not satisfied with reinventing the internet, Google's boffins have now come up with a system to track the spread of flu across the United States by referencing the terms used in Google searches.

The system, called Google Flu Trends, plots the location of searches for flu-related terms, to come up with a flu map. The early- warning data is then passed on to the US Centres for Disease Control and Prevention (CDC) based in Atlanta, Georgia, which can choose to take preventive action such as distributing more flu vaccines in the affected areas.

The scheme avoids privacy issues by relying only on aggregated data that cannot be traced to individual searchers.

The flu records provide timely data that could be two weeks ahead of government figures. 'The data are really, really timely,' said Dr Lyn Finelli, chief of influenza surveillance at the CDC.

'They were able to tell us on a day-to-day basis the relative direction of flu activity for a given area. They were about a week ahead of us. They could be used ... an early warning signal for flu activity.'

Between five to 20 per cent of the US population contracts the flu each year, Finelli told the New York Times Wednesday, leading to roughly 36,000 deaths on average.

Google developed the model by comparing hundreds of billions of Google searches with CDC data on outbreaks. 'Our team found that certain aggregated search queries tend to be very common during flu season each year,' Google said in their official blog on the topic.

'We found that there's a very close relationship between the frequency of these search queries and the number of people who are experiencing flu-like symptoms each week,' the blog said.

'This seems like a really clever way of using data that is created unintentionally by the users of Google to see patterns in the world that would otherwise be invisible,' said Thomas W Malone, a professor at the MIT Sloan School of Management in Cambridge, Massachusetts.

'I think we are just scratching the surface of what's possible with collective intelligence.'

Google Flu Trends is accessed at: http://www.google.org/flutrends/